Effective and Cost Efficient Catalyst (Sawdust)

(The following paper appeared as a Technical Report in the �Afterwords� section of the Mar/Apr 1994  issue of the Journal of Forensic Identification)

Metro--Dade Police Department
Miami, Fl.

When cellulose, regardless of the form used, is impregnated with sodium bicarbonate (baking soda), it reacts immediately with low viscosity super glue and develops latent fingerprints within three to five minutes on plastic, glass, and metallic items.  Medium viscosity super glue requires a longer reaction time before the release of fumes, but can be equally productive.

Pure, raw sawdust from unprocessed wood, that which has not been chemically or pressure treated, painted, varnished or otherwise altered, is a convenient and inexpensive source of cellulose.  When combined with sodium bicarbonate, it forms a stable catalyst that can be used in any type of super glue fuming.

The following catalyst mixture was found to be the most effective for super glue fuming:

By volume, two heaping teaspoons of sawdust are added along with one teaspoon of baking soda into a zipper--seal bag.  The two components should be mixed by shaking well.  Larger quantities may be prepared using the same ratio, by volume, of two parts of sawdust with one part of baking soda.  The mixed catalyst should remain stored in the zipper--sealed bag, and the bag should be thoroughly shaken prior to each use.

Approximately one teaspoon of the sawdust--baking soda catalyst is placed in a weigh dish and saturated with low viscosity super glue.  Normal amounts of super glue are used according to what have given the best results for the container.  No external heat should be used; however, better results are usually obtained when the sawdust mixture is slightly warmed prior to super glue application.  Excellent results are obtained on glass, metal, and all types of plastic.

The sawdust--baking soda mixture is a safe, effective catalyst that significantly increases the efficiency of super glue processing.  Although other procedures for super glue fuming work well, sawdust catalyst offers the advantages of two inexpensive and readily available ingredients along with simplicity and convenience in mixing, storing, and transporting.  Any method which promotes super glue application, particularly in field use, is worth considering.

For further information, contact:

William C. Sampson
Metro--Dade Police Department
Crime Scene Investigations Bureau
9105 NW 25 Street, Room 2180
Miami, FL 33172
(305) 471--2035

This article was reprinted in �THE PRINT� 10(5),May 1994, pg 6
and has been obtained from the online library provided by the

Southern California Association of Fingerprint Officers